The Glock 23/32 grip fits my hand pretty well as is size wise, but I did find undercutting the triggerguard made a world of difference in getting a solid grip on the gun. Since this gets your hand higher up and puts less of your hand on the palm swell it may act as a "grip reduction". You also may consider dremeling off checkering (and maybe a tad deeper) and stippling or grip taping it to regain some texture.

I have a standard Glock 21 and am considering dremeling the top part of backstrap where the web of my hand fits to alleviate some of the 21's boxy feel; however, I have not figured out how to do this cleanly. The trigger undercut is easy since the Dremel drum fits nicely in this space.

Thanks SpaceMonkey. I've already been considering doing the undercut. In fact, that was one of the mods I did on the lower that was swapped out. I mentioned that the GR was one of the mods that I didn't regret. The undercut was also a mod that I didn't regret.